Adrohan is right. For most people rangers are without a doubt the most boring class to level and they rival druids as the worst class to level. However i enjoyed leveling my ranger more than my mage rogue or warrior. Dont really know why lol. Just found it better than the rest
Whilst rangers are one of the hardest classes to level, there is the most upside of all classes once you reach end game level imo. They are raid boss powerhouses and quite often you will find that rangers get the kills over rogues and mages and any dps warriors. Definately worth it to stick it out as a ranger.
Like what others have mentioned in this thread, look for a group to level with and venture into the boggan caves where you gain much better exp than the weaker noghans through the tunnels.
Similarly, if you work your way through the otherworld quest chain you will eventually come to a repeatable quest where you must kill a bridge sentinel. This can be done in groups and is quite easy and fast. The mob has a fairly quick respawn so you can grind out levels with friends there until the exp starts to drop off if you enkoy it there. There is also bounties and arena quest that you can do each day for that bit of extra exp
Ventius - level 227 ranger of dawn
Ventius - level 222 noob ranger of Enigma
Ventius - level 163 druid
Your newest blue name who has dreams to one day be purple